This invention relates to a hub clutch assembly for selectively transmitting driving force between a wheel axle and a wheel hub, and more particularly a hub clutch assembly having a four-wheel drive mode indicator means that is simple in structure.
A part-time four-wheel drive vehicle has hub clutches mounted between the front wheel hubs and the front axle to selectively transmit torque between the wheels and the axle.
A conventional such hub clutch has an axially slidable slide gear mounted on the axle. By engaging this gear with the wheel hub, the axle is rigidly coupled to the wheel hub (4WD mode). By disengaging the slide gear, the axle is disconnected from the wheel hub (2WD mode). Fluid pressure such as air pressure is used to move the slide gear between the 2WD and 4WD positions.
Such a hub clutch assembly has to have an indicator means which can notify the driver behind the wheel whether the drive mode is now in the 2WD or 4WD position.
Such a drive mode or position indicator is disclosed in unexamined Japanese patent publication 1-186434 and comprises sensors for detecting the 2WD and 4WD positions of the slide gear moved by pressure fluid, and an indicator means electrically connected to the sensors for indicating whether the current drive mode is in the 2WD or 4WD position.
Such sensors are extremely complicated in structure and expensive to manufacture.
An object of this invention is to provide a hub clutch assembly having a 2WD/4WD position indicator means that is simple in structure and includes a pressure detector for detecting a negative pressure used to change the drive mode.